Green’s Dictionary of Slang

(Can./US) a drinker of cheap alcohol, or some substance, e.g. paint-thinner, bay-rum, that can substitute; the liquids themselves.

1984		Partridge DSUE (8th edn) 994/2: since ca. 1920.
1988		M. Atwood Cat’s Eye (1989) 278: The beer parlours are divided into two sections. The Men Only sections are where the rowdy drunks and rubby-dubs hang out.
1991		(con. 1920s) O.D. Brooks Legs 111: We saw a rubby passed out in a doorway, a half-bottle of rubbing alcohol lying on his chest.